This invention relates to a silver oxide layer formed in a manner so as to enable the layer to absorb and/or reflect ultraviolet (UV) radiation, and a method of making the same.
Silver (Ag) layers are commonly used in low emissivity (low-E) coating systems. For example, see U.S. Pat. Nos. 5,770,321, 5,270,517, and 4,462,883, the disclosures of which are all hereby incorporated herein by reference.
For example, in the aforesaid xe2x80x2321 patent, a low-E coating system provided on a substrate includes the following layer stack: titanium dioxide, silicon nitride, nickel-chrome (NiCr), silver (Ag), nickel-chrome (NiCr), and silicon nitride. The silver (Ag) layer is sandwiched between the two NiCr layers, and is formed using a conventional sputtering process with a silver target. Specifically, the xe2x80x2321 patent states that the silver layer is sputtered using an average voltage of 425 volts, an average current of 25.90 amps, 12.71 kW, and in a nitrogen atmosphere (530 sccm) at a pressure of 1.5xc3x9710xe2x88x923 Torr. When deposited in such a manner, a silver layer can function to efficiently reflect and/or absorb infrared (IR) radiation.
Unfortunately, when deposited using conventional sputtering techniques, such silver (Ag) layers are not capable of absorbing and/or reflecting significant amounts of ultraviolet (UV) radiation. It is believed that this is because conventional sputtering devices tend to deposit sputter-coated silver layers in a manner such that they are not particularly dense.
In view of the above, it will be appreciated by those skilled in the art that there exist a need in the art for a silver (Ag) inclusive layer (e.g., a silver oxide layer) which is capable of absorbing and/or reflecting significant amounts of UV radiation. There also exists a need in the art for a method for depositing a silver inclusive layer that is capable of absorbing and/or reflecting significant amounts of UV radiation.
It is a purpose of different embodiments of this invention to fulfill any and/or all of the above described needs in the art, and/or other needs which will become apparent to the skilled artisan once given the following disclosure.
An object of this invention is to provide a silver oxide (AgO) inclusive layer capable of reflecting and/or absorbing significant amounts of ultraviolet (UV) radiation. Such a silver oxide layer may be utilized by itself, or alternatively within the context of a low-E or other type of coating system.
Another object of this invention is to provide a method for depositing a silver oxide inclusive layer that is capable of reflecting and/or absorbing significant amounts of UV radiation.
Another object of this invention is to sputter-coat a silver inclusive layer on a substrate, and either simultaneously or shortly thereafter bombard the silver inclusive sputter-coated layer with at least oxygen (O) ions from an ion beam source. The oxygen ions tend to densify the silver inclusive layer and transform it into a silver oxide (AgOx, where x is preferably from 0.8 to 1.2, most preferably about 1.0) inclusive layer. The increased density of the layer caused by the bombardment of oxygen (O) ions causes the layer to absorb and/or reflect increased amounts of UV radiation.
Silver oxide inclusive layers according to certain embodiments of this invention may be fully oxidized. In other embodiments, silver oxide layers of this invention need only be partially oxidized. It is noted that the more a silver layer is oxidized, the more UV radiation that it can reflect and/or absorb.
Yet another object of this invention is to fulfil any and/or all of the aforesaid listed objects and/or needs.
Generally speaking, certain embodiments of this invention fulfill one or more of the aforesaid needs and/or objects by providing a method of forming a silver oxide inclusive layer comprising the steps of:
providing a substrate; and
forming the silver oxide inclusive layer on the substrate utilizing at least an ion beam including oxygen ions.
Certain embodiments of this invention further fulfill one or more of the aforesaid needs and/or objects by providing a coated article capable of reflecting or absorbing significant amounts of ultraviolet (UV) radiation, the coated article comprising:
a substrate;
a silver oxide inclusive layer provided on said substrate; and
wherein said silver oxide inclusive layer has a density of at least about 5.0 grams per cubic centimeter (gms/cm3).